1. Field of the Invention
The present invention relates to a recording media cartridge such as a magnetic tape cassette. More specifically, the present invention relates to a recording media cartridge, e.g. a magnetic tape cassette, wherein a lid urging or biasing member such as a lid spring can be made of resin and the recording media cartridge with a lid spring made of resin as the lid urging member allows the omission of the sorting labor upon disposal of the cartridge as well as the reduction in the assembling steps of the cartridge, and moreover the decrease in the environmental impact; and a recording media cartridge, e.g. a magnetic tape cassette such as a digital video cassette (DVC) made effective in reducing the environmental impact.
2. Description of the Related Art
As a recording/reproducing tape cassette or cartridge used in a video tape recorder or video camera for business use or of consumer-oriented, or again, as a large capacity recording medium for data back-up in an external storage device such as a computer, is usually known a magnetic tape cassette or cartridge (hereinafter represented by “magnetic tape cassette”) which has a pair of reels around which a magnetic recording tape as recording media is wound (in the case of so-called two-reel type) or a single reel on which a magnetic tape is wound (in the case of so-called one-reel type) rotatably contained in a case body (casing or cassette case) composed of an upper half and a lower half. Examples thereof include a magnetic tape cassette whose structure and dimension are standardized in JIS X6127, X6129, X6130, X6171 or X6172, or ECMA-288. A magnetic or magneto-optical disk cartridge using a magnetic or magneto optical disk as recording media is also well known as a large capacity recording medium.
Such a recording media cartridge as a magnetic or magneto-optical disk cartridge and a magnetic tape cartridge or magnetic tape cassette referred to above is used for data storage in a computer etc. to retain important information recorded therein, so that it is produced with various protection mechanisms added thereto for preventing a damage of a magnetic or magneto-optical disk, or a jamming of a magnetic tape or inadvertent draw-out thereof.
For example, in a conventional magnetic tape cassette, a magnetic tape taken up or rewound between a pair of tape reels is extended across an opening portion provided in the front surface of a case body and travels through this portion to be brought into contact with a magnetic data reading/recording device of a recording/reproducing apparatus in order that magnetic data is read or recorded. In order to protect the magnetic tape at this portion and to enhance dust-proof property of the opening portion, a front lid is mounted in a manner capable of opening/closing for this front surface opening portion.
This will now be described specifically with respect to a two-reel type magnetic tape cassette.
FIG. 26 is a partially exploded perspective view showing a structure of a conventional general magnetic tape cassette. As shown in FIG. 26, a case body of a magnetic tape cassette 400 is composed of an upper half 402 and a lower half 404 coupled in a capped manner, and, between these two halves, a magnetic tape 408 wound between a feed side reel 406a and a take-up side reel 406b is received.
A lid (front lid) 410 for covering and protecting the magnetic tape 408 during non-use of this magnetic tape cassette 400 is mounted rotatably around a pin (not shown) in the front surface of the upper half 402. Also, a lock mechanism (lid lock mechanism) composed of a lid lock member 424 (see FIG. 28) and the like is provided on the lower half 404 in order to lock the lid 410 so as not to open during non-use of this magnetic tape cassette 400.
Incidentally, the above-described lid lock mechanism is normally provided corresponding to only one end of the lid 410. FIG. 27 is a perspective view of the one end portion of the lid 410 (the end portion on the side on which the lid lock mechanism is provided as described later). As shown in FIG. 27, a rotary shaft 414 is provided inside a side surface of the lid 410, and then the lid 410 is fitted on the upper half 402 to be rotatable as indicated by an arrow A around this rotary shaft 414.
Also, a projection 416 serving as a reel release key is provided to the rotary shaft 414. Furthermore, a hole (lid lock hole) 418 for receiving a constituent member (lid lock key 428) of the lid lock mechanism is provided in the side surface of the lid 410 in order not to accidentally open the lid 410 during non-use of the magnetic tape cassette.
FIG. 28 is an enlarged perspective view showing a vicinity of a reel lock member 412b. As shown in FIG. 28, the reel lock member 412b is provided with a pin 420, which is fitted into the center of the member 412b, supported rotatably around the pin 420, formed at one end with a wall-like member 413a, and formed at the other end with a pawl-like member (braking pawl) 413b. The braking pawl 413b is engaged with an engagement tooth 407 provided on a circumferential edge of a reel flange 406b to thereby limit the rotation of the reel 406b, thus preventing loosening of the magnetic tape.
Incidentally, normally, the reel lock member 412b is urged or biased in a direction in which the braking pawl 413b is engaged with the engagement tooth 407 by a coil spring 422.
Also, a lid lock member 424 is arranged in the vicinity of the reel lock member 412b. This lid lock member 424 is provided with a pin 426, which is fitted into one end portion 424a of the member 424, and engaged therewith as shown in FIG. 28. The lid lock member 424 is rotatable around this pin 426 and a lid lock key 428 in a projecting shape is provided at the other end portion 424b. 
As shown in FIG. 26, the lid lock key 428 projects to the outside from a hole 404a formed in the side wall of the lower half 404 and engaged with the lid lock hole 418 provided in the side wall of the lid 410 shown in FIG. 26 or 27 so as to limit (lock) the lid 410 for preventing it from rotating.
As shown in FIG. 28, normally (in non-use of the magnetic tape cassette), the lid lock member 424 is urged by an end portion of the coil spring 422 for urging the above-described reel lock member 412b so that the lid lock key 428 is engaged with the lid lock hole 418 of the lid 410 to thereby limit the lid 410 so as not to rotate.
When the magnetic tape cassette 400 is loaded in the recording/reproducing apparatus, a member on the recording/reproducing apparatus side pushes a lower portion of the end portion 424b of the lid lock member 424 in a direction indicated by an arrow B in FIG. 28, whereby the end portion 424b of the lid lock member 424 is rotated in a direction indicated by an arrow C in FIG. 28. With this, the lid lock key 428 is released from the engagement with the lid lock hole 418 of the lid 410, whereby the lid 410 can be rotated in a direction indicated by an arrow A in FIG. 29.
As described above, when the lid 410 is rotated in the direction indicated by the arrow A in FIG. 29, the rotary shaft 414 is also rotated in the direction indicated by the arrow A as shown in FIG. 29. With this, the reel release key 416 provided on the rotary shaft 414 urges the wall-like member 413a of the reel lock member 412b in a direction indicated by an arrow D. As a result, the reel lock member 412b is rotated around the pin 420, and the braking pawl 413b provided at one end thereof is moved in a direction indicated by an arrow E in FIG. 28 to thereby release the engagement with the engagement tooth 407 of the reel 406b. In this manner, the reel 406b becomes rotatable.
FIG. 30 is a perspective view showing a mounted state of the lid spring for urging the lid 410 in a closing direction. In FIG. 30, reference character 430 denotes a lid spring, reference character 430a denotes a U-shaped engagement portion provided at one end thereof for engaging with the projection 416 on the rotary shaft 414 of the lid 410, and reference character 430b denotes an engagement portion at the other end of the lid spring for engaging with an engagement recess portion 402a of the upper half 402. When the lid 410 is opened in a way indicated by an arrow F, the lid spring 430 having such a configuration as above works inversely, that is to say, so as to close the lid 410.
FIGS. 31A and 31B are perspective views each showing the inner surfaces of an upper half of a conventional magnetic tape cassette and a lid fitted on the upper half, FIG. 31A illustrating the case where the lid is closed and FIG. 31B the case where the lid is opened.
As seen from the figures, a lid 460 is fitted on a front edge 453 of an upper half 452. The lid 460 has rotary shafts (hereinafter referred to simply as shafts) 464 projected from side surfaces 457 on both its sides toward the inside of the upper half 452, which shafts 464 are rotatably supported on shaft supports 461 provided at front ends 459 of side walls of the upper half 452, respectively.
On a shaft end 465 of the shaft 464 is mounted a lid spring 480 which is a torsion coil spring. In the lid spring 480, a coil portion 480c is fitted onto the shaft end 465, a U-shaped (semicircular) engagement portion 480a at one end of the spring 480 is engaged with a projection (engagement rib) 466 projected from the circumferential surface of the shaft 464, and an engagement portion (elastic arm portion) 480b at the other end is anchored to an engagement recess (anchor groove) 452a formed in a front part of the inner surface of the upper half 452. The lid spring 480 serves as a lid urging member which urges the lid 460 against the upper half 452 in the closing direction.
When the lid 460 is in a closed state as shown in FIG. 31A, an opening/closing mechanism for the lid 460 is locked by a lid lock mechanism composed of a lid lock member 474 (see FIG. 28) which is provided in the part of a lower half 454 directly below the side surface 457 of the upper half 452.
The lid 460 in a closed state as above can be opened by pushing in a lid release member (not shown) whose top portion is protruded from a lid lock hole 468 bored in the side surface 457 to cancel the lock by the lid lock member 474 (see FIG. 28) provided on the lower half 454 and then rotating the lid 460 about the common axis of the shafts 464 to tip up it as shown in FIG. 31B. In this way, a front opening of a case body of the magnetic tape cassette is made open, as the lid 460 being urged in a rotating direction for closing by the lid spring 480.
Next, a general structure of a digital video cassette (DVC) as a magnetic tape cassette using a different type of lid will be described.
FIG. 32 is an exploded perspective view showing a structure of the above-described DVC that is one example of a magnetic tape cassette. As shown in FIG. 32, a case body 610 of this magnetic tape cassette is constituted by coupling in a capped manner an upper half 620 and a lower half 622, each of which has a bottom plate and a circumferential wall. A magnetic tape 626 wound around tape reels 624 on a pay-out side and a take-up side is received between these two halves.
The tape reels 624 are restricted in slippage in the direction parallel to the plane of the bottom plate 622a of the lower half 622 by a plurality of restriction ribs provided upright on the bottom plate 622a in such a manner that they extend along the circumferences of the respective tape reels. Also, an opening is provided in a bottom plate of the upper half 620 so that the amount of wound magnetic tape 626 in the tape reels 624 may be confirmed, and a transparent window (see-through window) 620a is provided for closing this opening.
Also, a pair of reel urging plate leaf springs (hereinafter referred to as reel pressing springs) 638 are provided on the inner surface (the lower surface in the drawing) of the upper half 620 correspondingly to the respective tape reels 624. The respective reel pressing springs 638 are fixed to the inner surface of the upper half 620 by ultrasonic welding, hot welding, or the like to urge the corresponding tape reels 624 toward the lower half 622 side.
A lid (front lid) for covering and protecting the magnetic tape 626 in non-use of this magnetic tape cassette is mounted on the front surface (on the left side in the drawing) of the upper half 620. As will be described later, this lid is composed of three members, i.e., an outer lid 630, an upper lid 632 and an inner lid 634, which are mounted to make it possible to open an opening portion 628 of the magnetic tape cassette, respectively.
On extensions 640 located on both sides of the opening portion 628 provided on the front end side (on the left side in the drawing) of the lower half 622 are provided tape guides 646. Each tape guide 646 leads the magnetic tape 626 paid out by one tape reel 624 and taken up by the other tape reel 624 to cause it to pass through a predetermined position in the opening portion 628.
On the rear end side (on the right side in the drawing) of the lower half 622 is incorporated a tape reel lock member 636 having tape reel anchoring arms 636a and a slider body 636b. The slider body 636b is slidably held between a pair of guide ribs provided upright on the bottom plate 622a of the lower half 622. The tape reel lock g member 636 is urged by a helical compression spring 642 so as to cause the tape reel anchoring arms 636a to engage with engagement teeth 624a formed in the circumferences of lower flanges of the tape reels 624, respectively, to thereby prevent an inadvertent rotation of respective tape reels 624. Thus, the loosening of the magnetic tape 626 wound, etc. is prevented.
Among the outer lid 630, the upper lid 632 and the inner lid 634 each mounted on the upper half 620 as referred to above, the outer lid 630 has a flat portion and a side plate and from the inside of the side plate is protruded a lock pin 630a. On a side wall portion 622c as a part of the circumferential wall of the lower half 622, a lid lock member 644 is rotatably mounted, to which the lock pin 630a of the outer lid 630 is anchored when the outer lid 630 is in a closed state. The lid lock member 644 is urged in the direction for anchoring the lock pin 630a by a lid lock spring (not shown) also provided on the lower half 622.
Further, a safety plug 652 for preventing data recorded on the magnetic tape 626 from an erroneous deletion is mounted on the lower half 622. The safety plug 652 has a pawl protruding from its one side surface (on the right side in the drawing) and is so formed that the pawl projects from an opening provided in the circumferential wall of the upper half 620 to the outside, as the plug 652 being fitted in the lower half 622.
The safety plug 652 can be moved along a guide rib provided upright on the bottom plate 622a of the lower half 622 by manipulating the pawl from the outside. As a result, the safety plug 652 makes it possible with its bottom surface to close or open a detection hole provided in the bottom plate of the lower half 622. A recording device and the like read the state, namely a closed state or an open state, of the detection hole to determine whether new data can be written in the magnetic tape 626 or not.
The lower half 622 has a rectangular bottom plate 622a. The bottom plate 622a supports a pair of tape reels 624, around which the magnetic tape 626 is wound, in a rotatable manner. In addition, the bottom plate 622a has reel shaft insertion holes 622b for, when the magnetic tape cassette is loaded in a recording/reproducing apparatus, allowing reel shafts (not shown) to be inserted from the recording/reproducing apparatus into the tape reels 624 and rotating to drive the tape reels 624.
The bottom plate 622a further has the extensions 640 which extend from the right and left ends of the plate 622a forward. In the extensions 640 at both the right and left ends, the tape guides 646 in a cylindrical form are provided upright on the bottom plate 622a and perpendicularly thereto for leading the magnetic tape 626 extended between the tape reels 624 through a predetermined route to the front surface of the case body. The bottom plate 622a of the lower half 622 is partially cut out between the extensions 640 and the space thus made constitutes the opening portion 628 of the case body.
The upper and lower halves 620 and 622, the outer lid 630, the upper lid 632, the inner lid 634, upper and lower flanges of the tape reels 624, and so forth are each formed by injection molding. In a magnetic tape cassette, many other components formed by injection molding are used appropriately.
Considering the magnetic tape cassette having the thus described structure, a lid spring (torsion spring) 631 for urging the three members of the above-described outer lid 630, upper lid 632 and inner lid 634 in a direction for closing the opening portion 628 of the magnetic tape cassette is conventionally made of metal, fitted into the rotary shaft 630a of the above-described outer lid 630, and set as anchored to the upper half 620 and the outer lid 630.
As shown in FIGS. 33A and 33B, urging of the above described lid is performed by the lid spring 631, and this lid spring 631 is set as fitted between the upper half 620 and the outer lid 630 as described above. Here, FIGS. 33A and 33B are partially cross-sectional, enlarged side views showing a mounting state of a lid using a conventional lid spring made of metal, where FIG. 33A shows a closed state and FIG. 33B shows a flat state of the lid.
Incidentally, in recent years, as concern about the environmental issue is increased and an attention is paid to the adverse influence on the environment due to various kinds of wastes such as plastics and composite materials, it is becoming important to reduce the wastes or to use materials which do not cause the contamination of the atmosphere, water and soil and do not place the hindrance to the environmental preservation even when disposed of, i.e., to reduce the impact to the environment. For this reason, it is required also for the industrial products to take a configuration that may be incorporated into a recycling system.
Here, considering a recording media cartridge such as a magnetic tape cassette of various types constructed as described above, its major part including the case body is made of plastics and a metal material is used only in a part that needs relatively high strength or a part that needs elasticity. More specifically, in the magnetic tape cassette as such, each urging spring of the reel lock mechanism and the lid lock mechanism and further a lid spring are made of metal in view of durability.
However, when the thus constructed magnetic tape cassette is disposed of after use, it is necessary to disassemble the magnetic tape cassette and to pick up the metal-made springs and such a work needs manual labor. It is desired that such labor be removed as much as possible.
Especially in a conventional magnetic tape cassette such as, for example, shown in FIGS. 31A and 31B, the lid spring has the complicated shape as described above and requires such an arrangement that the coil portion 480c is fitted onto the shaft end 465 of the shaft 464, the engagement portion 480a is engaged with the projection 466, and the engagement portion 480b is anchored to the engagement recess (groove) 452a. Accordingly, the assembling work thereof is difficult, which is a cause of the prevention of improving the assembling property of the magnetic tape cassette.
In addition, the lid spring is hard to form with a resin material because of its configuration as a torsion coil spring and can not but be formed with a metal. The removal of the lid spring from the rotary shaft 464 is troublesome, making the disassembling of the magnetic tape cassette and the sorting of materials difficult. Thus, the sorting and collection of resin materials become difficult, a disadvantageous result to the reduction in the environmental impact.
If the magnetic tape cassette shown in FIG. 32 has such a structure as shown in FIGS. 33A and 33B, it is assembled in such a manner that the upper lid 632 and the inner lid 634 are mounted on the outer lid 630, then onto the rotary shaft 630a of the outer lid 630 is fitted the lid spring 631 made of metal, the whole assembly thus obtained is fitted into a rotary shaft engaging portion 620b, which is provided upright on the upper half 620, from the outside (on the front surface side), and finally one end of the spring 631 is anchored to the anchor portion in a clamped fashion. Such a procedure requires much labor since many components and members are to be handled at once.
On the other hand, the conventional lid spring 631 made of metal, which is used in the conventional magnetic tape cassette as described above, is not easy to remove when it is to be sorted and collected. In other words, the lid spring 631 can be removed only by disassembling at least the lid portion of the magnetic tape cassette. As a consequence, a problem arises that the sorting and collection of materials might not always be performed perfectly.